package com.tmpt.security;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

public class MySecurityFilter extends AbstractSecurityInterceptor implements Filter{

	//the others component have been defined in AbstractSecurityInterceptor
	private FilterInvocationSecurityMetadataSource securityMetadataSource;

	@Override
	public Class<?> getSecureObjectClass() {
		//下面的myAccessDecisionManager的supports方面必须返回true,否则会提醒类型错误
		return FilterInvocation.class;
	}

	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return this.securityMetadataSource;
	}

	public void destroy() {

	}

	public void doFilter(ServletRequest request, ServletResponse response,
						 FilterChain chain) throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);

	}

	public void invoke(FilterInvocation fi) throws IOException, ServletException{
		/*
		 * 核心的InterceptorStatusToken token = super.beforeInvocation(fi);
		 * 会调用我们定义的accessDecisionManager:decide(Object object)和securityMetadataSource
		  :getAttributes(Object object)方法。
		 */
		// object为FilterInvocation对象
		//super.beforeInvocation(fi);源码
		//1.获取请求资源的权限
		//执行Collection<ConfigAttribute> attributes = SecurityMetadataSource.getAttributes(object);
		//2.是否拥有权限
		//this.accessDecisionManager.decide(authenticated, object, attributes);
		InterceptorStatusToken token = super.beforeInvocation(fi);
		try {
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		} finally {
			super.afterInvocation(token, null);
		}

	}

	public void init(FilterConfig arg0) throws ServletException {

	}

	public FilterInvocationSecurityMetadataSource getSecurityMetadataSource() {
		return securityMetadataSource;
	}

	public void setSecurityMetadataSource(
			FilterInvocationSecurityMetadataSource securityMetadataSource) {
		this.securityMetadataSource = securityMetadataSource;
	}

}
